Process of preparing a silicamagnesia gel catalyst



Patented May 17, 1949 raocnss F PREPARING A sILIcA- MAGNESIA GEL CATALYST Eugene S. Corner, Roselle, N. J., assignor to Standard Oil Develo poration of Delaware Application August 21, 1946, Serial No. 692,123

No Drawing.

pment Company, a cor- 4 Claims. (01. 252-457) The present invention is concerned with a process for the preparation of improved catalysts. It more specifically relates to the preparation of improved catalysts suitable for use in cracking, reforming,isomerization, polymerization, and alkylation processes. In accordance with my process, an improved magnesia silica catalyst is prepared by aging the hydrogel at room temperatures for a time period determined by the concentration of the aqueous slurry of the hydrogel.

It is known in the art to improve the quality. of oils, particularly petroleum oils, by treating the same with catalysts under various operating conditions. For example, it is well known to treat petroleum oils boiling in the range above about 400 F. with a silica magnesia catalyst at temperatures in the range from about 600 F. to about 1100 F. in order to crack the oils and to secure petroleum oil fractions boiling in the motor fuel boiling range. It is also known in the art that synthetic porous solids, comprising silica and one or more metallic oxides, such as alumina, magnesia, zirconia, beryllium, eta, have catalytic properties for the treatment of mineral oils.

In the cracking of these mineral oils the propoxide or oxides incorporated with the silica,'the method of treatment during incorporation and the quantity or quantities incorporated. For instance, one general classification of synthetic contact masses consists of silica and alumina, with or without the addition of a third component such as zirconium or the like- Catalysts of this general class are characterized as those producing relativelylarge amounts of olefinic and isoparaflinic hydrocarbons having molecular weights from about 28 to about 56 or higher, and capable of producing naphthas in the gasoline boiling range which contain appreciable quantitles of mono and'poly-cycli'c aromatic hydro carbons. In general, this class of catalysts is highly desirable for the manufacture of aviation gasolines.

Another general classification of synthetic contact masses comprises silica and magnesia as the major oxides with or without the addition of alumina, calcium or the like. In comparison with the above discussed classification, the silicamagnesia type catalysts, during cracking, produce smaller quantities of hydrocarbons having molecular weights below about 58 and produce a substantial increase of hydrocarbons having desirable antiknock qualities, boiling in the range 26- 'erties of the catalyst will depend on the metallic I from about F. to about 450 F. vapor temperature. It is apparent that these catalysts are more suited for refining operations, designed to produce high quality motor gasolines, provided these catalysts can be prepared to possess desirable activity and stability characteristics. invention is concerned with a process for producing superior characteristics in a commercially desirable manner by aging the catalysts for a time period which is the function of the concentration of the catalysts in the water slurry.

Heretofore, these catalysts have been prepared by various procedures. One method employed in the manufacture of these catalysts is to prepare a silica hydrogel by mixing an alkali metal silicate and an acid, such as sulfuric acid. The hydrogel is washed and soaked in a solution containing a salt of, magnesium, manganese, beryllium, zirconium, or a salt of any other desirable metal with which it is to impregnate the silica hydrogel. The concentration of thesolution with respect to the salts is adjusted to give the composition desired in the final catalysts. After the impregnation step, the hydrogel is generally treated with a solution of ammonia in order to precipitate the magnesia and the oxide of the added metal within the gel structure. The by,- drogel is washed free of soluble salts, dried and activated.

Another method utilized for the preparation of these catalysts is to prepare a silica hydrogel by mixing sodium silicate and sulfuric acid. The silica hydrogel is washed and dried. The dried gel is then mixed by grinding with magnesia and the oxide of a third metal, if it is desired to impregnate the hydrogel with the third component. The catalyst is dried at a temperature in the range from about 200 F. to 300 F. and activated.

Another method of preparing silica magnesia catalysts is to mull magnesia with the silica hydrogel in water. The ratio of water to the total solids is usually in the range from about 5 to about 12 parts by weight of water per part by weight of solids. The mulling is usually carried out by suitable means such as in a bowl, tube,

rod mill, pan mill or the like. Mulling is conducted overv a period of about 5 to about 10 hours under conditions to form a very finely divided product which, in many cases, is a semifluid. The material is slowly dried in a convex I 3 The dried catalyst is activated temperature in the; range it I by the. addition r I 3 ides maybe E ica hydrogeL chromium,-copper and iron.

'ing'ah I 1400 I 1?..- generally at a te l atureof. about 1250 F. for a period oi. aboutthr'ee hoursi From the'p'receding discussions it is apparent thatthe general procedure for the preparation about 1150 to by'heatingat a.

Int room: temperature (68 to :75 F.) without I drying iori 36 no 1 The catalyst wasthen dried I 1 i at a temperature of about 350; F. I .'I'he catalyst i 3 was pelleted and activated by treating it atfa I I temperature of 1250'3F. fora period of .3 hours. l I A catalyst was prepared in a similar manner;

of these catalysts is to prepare the silica hydrosoli 5 then. mixed by various IV, and VIII of the periodic table. these oxmixed with the sllicasolorthe sil-f cation are, forexample; manganese zirconium,

beryllium, zinc, titanium, aluminum.

In the usual procedure it has in the range from about 200 F. to 350 j j then to activate the dried catalyst at; a temper- I f atur'e in the range from aboutilllOP-Rto '1450P:F..

generally at a temperature of about 1250* for I .aperiod cfjirom about 2 to 6 hours. I have now. however. discovered that the catalyst unexpected, desirable results are ser d i aging'period be employed prior, to drying I sodium silicate to sulfuric acid. .The resulting sllicahydroisol, hydrogel. or I I g :10 Im'eans. withmagnesia to'secure the desired silica Suitable metals' Of this classiflii I I I .20 heretofore been I thepractice to dry the hydrogel' at a-temperature F. and

idioms and up to 400 F. and point.

I From the above, data it i cat'alyst aged, for 36 hours wasappreciahly more: i

cured with respect to the initial activityof. the I catalyst Also hyemploying myprocedure the, i catalysts. will possess improved team stabilities; I jBy steam stability is meant the ability of catalyst I i I to retainits catalytic activity afterit has been "exposed to the effect of steam. It is very im-e purge the catalyst before it is introduced into these vessels. Steam is particularly detrimental to catalyst of the present invention at regeneration temperatures in that it appreciably lowers the catalytic activity. Thus, it is obvious that my process which produces catalysts of improved steam stabilities is highly desirable. In accordance with my invention I propose to age the aqueous slurry of catalysts of the present invention for a period of from about 8 to 150 hours, at a temperature in the range from about 60 F. to 90 F. The period of time over which I age the catalyst of the present invention is a function of the concentration of the catalyst in the aqueous slurry.

The process of my invention may be more readily understood by reference to the following examples illustrating the same.

EXAMPLE I A sodium silicate solution (NazO.3.25SiOz) solution having a specific gravity of 1.21 was mixed with a sulfuric acid solution having a specific gravity of 1.19. Approximately 806 parts by weight of the sodium silicate solution was mixed with 396 parts by weight of the sulfuric acid solution. The resulting washed silica hydrogel had 8. S102 concentration of 13.01%. The silica hydrogel was mixed with magnesium oxide in proportions to give 65% S102 and 35% MgO on a dry basis. The magnesium oxide contained 94.9% magnesium oxide by weight. Th mixture 01' silica hydrogel and magnesium oxide was ball milled for six hours at a temperature of about 75 F. together with 1300 parts of distilled water.

i I portant; that catalysts possess good steam sta j I j bilities. tie, that they resist the; actionofsteamj, since steam is present in both the reactor and .re-'-,

I 'g'enerator; The steamisgenerally'cmployed td I to that described above except that it was dried 7 I immediately: after mixing. without any inter- I mediate. a ng period.

I These catalysts, were used: to cracl: an East I I f magnesia composition I If it isdesired to prev- Z I 3 Texas gasjoil which boiledabovei about .400 F, i 1 i I "pare a three-component catalyst comprisin ior I examplm oxidesof the'metalsj :oifgroup Ill,- III,

me. of catalyst per hour.

vol. of catalyst: per hour.)

o eration OperationII .Cat alystA ge (as? to 15 unheard. so I I I I CatalystDi-ied 2; -;F.. I W350 D+L ..percent.- I I 50 43 i Liquid productcomprlsing hydrocarbons, of 4 or has fcai'bon' i efiective in, the cracking. of this gas 011.;

" 'Exmrrenj A-catalystiwas preparedas describedin Example I I except thatit was dried at-.220 F. Another 7 catalyst was prepared and dried at 220 F. except; that it wasnot aged in accordance with my process.-

J f.These catalysts were used to crack: an East Texas gas oil at-850 F. I Aieed rate of 0.6 volume I of gas oil per volume of catalyst per hour was emoperations are tabulated as follows: 7 I [East Texas gas oil cracked at 850 F. Feed rate 0.6 vol. 01 feed per vol. of catalyst per hour.)

Operation III Operation IV Catalyst Aged (68 to 75 F.)- hours.. so 0 Catalyst Dried .311. 220 220 D+L -.per cent.- 54 46 EXAMPLE III mulled for three hours and aged for various time periods. Catalysts 8 to 10, containing 12%% solids in the slurry, were mulled for 3 /2 hours and aged for various time periods.

These catalysts were used to crack an East Texas gas oil which boiled above about 400 F. at a temperature of 1250 F.,and at 0.6 volume of feed per volume of catalyst per hour. The initial effectiveness of the respectivecatalysts is readily apparent from the data.

The catalysts were then steamed for 24 hours at 60 lbs. per sq. in. at a temperature of 1060 F. These steamed catalysts were used to crack East Texas gas oils under similar conditions. The offectiveness of the steamed catalysts is also readily apparent from the data.

Themixture was aged by allowing. it to stand apparent that my I ployed. The results secured on the respective Eject of doing on initial activity and steam sta- Percent of recovered liquid product boiling in the butane to 400 F. gasoline range. Testing conditions were: cracking tempera- Euro 850 F., iced rate 0.6 V./V. hr.

# Steamed 24 hours at l050 d at 60 p. s. l. g.

My invention comprises in general the preparation of improved active catalysts of the type described, by aging the catalysts for a time period before drying and activating. My invention may be varied within the scope outlined. However, in general, I prefer to age the catalysts at temperatures in the range from about 60-90 F., preferably eta temperature of in the range from about 70 79 for a time period of from about 8 to 159 hours. In accordance with the preferred modification of my invention, it the aqueous slurry contains from about 10 to 17% solids in the slurry, I prefer to age my catalysts at a temperature of about 'l 0-'l5 F. for a time period of about 8 to 30 hours. However, if the concentration of the solids in the slurry exceeds about 17%, the catalysts should be aged for a period not less than 48 hours, and preferably should be aged at a temperature of from lo-75 F., for a period of about 50 to 150 hours.

The process of my invention is not to be limited by any theory as to mode of operation, but only in and by the following claims.

I claim:

1. A process for preparing a catalyst comprising silica and magnesia. adapted tor the conversion of hydrocarbon oils and" having improved steam stability, which comprises preparinga. hydrous oxide of silica selected from the class con slstlng of silica hydrogel and gelatinous precipi tated silica, intermixingsaid hydrous omde with f magnesia and water to form a slurry containing not less than about 10% ct solids, mulling said slurry in a substantial period sufllcient to form i an intimate homogeneous mixture of said silica and said magnesia, thereafter aging the mulled slurry at a temperature between about F. and F. for a period of about 8 to hours and thereafter drying and activating the resulting product.

2. The process defined by claim 1 wherein the hydrous oxide of silica is silica hydrogel.

3. The process defined by claim 1 wherein the slurry-contains from 10% to 17% solids andthe I aging period is from about 8 to about 30 hours.

4. The process defined by claim 1 wherein the EUGENE 3. .14.

REFERENCES CITED UNITED STATES PATENTS Number Name Date 1,900,859 Connolly et al Mar. '1, 1933 2,340,934 Connolly Feb. 8, 1944 2,343,295 Baille et al Mar. 7, 1944 2,343,731 Baille et a1. Mar. 7, 1944 r 2,390,556 Ruthrufi Dec. 11, 1945 2,412,958- Bates et a1. Dec. '24, 1946 

